Delete non number containing braces from string

user_688720 0
Viewed 49

A string may contain non-number in braces which needs to be deleted. Input can be multiline too, for example :
input:

# (1437)  
# {19} (917) (1437)  
# {19} (1437) [1449] [2474] [2098] [1351] [508]   [969]( MONDAY) [sunday]

desired output:

# (1437)  
# {19} (917) (1437)  
# {19} (1437) [1449] [2474] [2098] [1351] [508] [969]

However the below regex instead of removing just ( MONDAY) [sunday] removes the last line completely.

$re = '/^(#\h*)((\[\d+]|\{\d+}|\(\d+\))(?:\h+(?3))*)$/m';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
echo implode("\n", array_map(fn($x) => $x[1] . implode(' ', array_unique(explode(' ', $x[2]))), $matches));
preg-match-all preg-match preg-replace php regex
1 Answers

In php (PCRE) flavor you may use this regex with conditional construct:

(?:(\()|({)|\[)\D*(?(1)\)|(?(2)}|]))\s*

RegEx Demo

RegEx Details:

  • (?:: Start non-capture group
    • (\(): Match ( and capture in group #1
    • |: OR
    • ({): Match { and capture in group #2
    • |: OR
    • \[: Match a [
  • ): non-capture group
  • \D*: Match 0 or more non-digits
  • (?(1)\): If group #1 is present then match )
    • |: OR
    • (?(2)}|]): If group #2 is present then match } else match ]
  • ): End of conditional construct
  • \s*: Match 0 or more whitespaces

Code:

$r = preg_replace('/(?:(\()|({)|\[)\D*(?(1)\)|(?(2)}|]))\s*/', '', $s);

A bit more efficient version of above regex (avoids backtracking):

(?:(\()|({)|\[)(?(1)[^)\d]*\)|(?(2)[^}\d]*}|[^]\d]*]))\s*

RegEx Demo 2

user_5482250
Related